When Western Digital introduced its Ultrastar DC SN861 SSDs earlier this year, the company did not disclose which controller it used for these drives, which made many observers presume that WD was using an in-house controller. But a recent teardown of the drive shows that is not the case; instead, the company is using a controller from Fadu, a South Korean company founded in 2015 that specializes on enterprise-grade turnkey SSD solutions.
The Western Digital Ultrastar DC SN861 SSD is aimed at performance-hungry hyperscale datacenters and enterprise customers which are adopting PCIe Gen5 storage devices these days. And, as uncovered in photos from a recent Storage Review article, the drive is based on Fadu's FC5161 NVMe 2.0-compliant controller. The FC5161 utilizes 16 NAND channels supporting an ONFi 5.0 2400 MT/s interface, and features a combination of enterprise-grade capabilities (OCP Cloud Spec 2.0, SR-IOV, up to 512 name spaces for ZNS support, flexible data placement, NVMe-MI 1.2, advanced security, telemetry, power loss protection) not available on other off-the-shelf controllers – or on any previous Western Digital controllers.
The Ultrastar DC SN861 SSD offers sequential read speeds up to 13.7 GB/s as well as sequential write speeds up to 7.5 GB/s. As for random performance, it boasts with an up to 3.3 million random 4K read IOPS and up to 0.8 million random 4K write IOPS. The drives are available in capacities between 1.6 TB and 7.68 TB with one or three drive writes per day (DWPD) over five years rating as well as in U.2 and E1.S form-factors.
While the two form factors of the SN861 share a similar technical design, Western Digital has tailored each version for distinct workloads: the E1.S supports FDP and performance enhancements specifically for cloud environments. By contrast, the U.2 model is geared towards high-performance enterprise tasks and emerging applications like AI.
Without any doubts, Western Digital's Ultrastar DC SN861 is a feature-rich high-performance enterprise-grade SSD. It has another distinctive feature: a 5W idle power consumption, which is rather low by the standards of enterprise-grade drives (e.g., it is 1W lower compared to the SN840). While the difference with predecessors may be just 1W, hyperscalers deploy thousands of drives and for their TCO every watt counts.
Western Digital's Ultrastar DC SN861 SSDs are now available for purchase to select customers (such as Meta) and to interested parties. Prices are unknown, but they will depend on such factors as volumes.
Sources: Fadu, Storage Review
StorageSamsung had quietly launched its BM1743 enterprise QLC SSD last month with a hefty 61.44 TB SKU. At FMS 2024, the company had the even larger 122.88 TB version of that SSD on display, alongside a few recorded benchmarking sessions. Compared to the previous generation, the BM1743 comes with a 4.1x improvement in I/O performance, improvement in data retention, and a 45% improvement in power efficiency for sequential writes.
The 128 TB-class QLC SSD boasts of sequential read speeds of 7.5 GBps and write speeds of 3 GBps. Random reads come in at 1.6 M IOPS, while 16 KB random writes clock in at 45K IOPS. Based on the quoted random write access granularity, it appears that Samsung is using a 16 KB indirection unit (IU) to optimize flash management. This is similar to the strategy adopted by Solidigm with IUs larger than 4K in their high-capacity SSDs.
A recorded benchmark session on the company's PM9D3a 8-channel Gen 5 SSD was also on display.
The SSD family is being promoted as a mainstream option for datacenters, and boasts of sequential reads up to 12 GBps and writes up to 6.8 GBps. Random reads clock in at 2 M IOPS, and random writes at 400 K IOPS.
Available in multiple form-factors up to 32 TB (M.2 tops out at 2 TB), the drive's firmware includes optional support for flexible data placement (FDP) to help address the write amplification aspect.
The PM1753 is the current enterprise SSD flagship in Samsung's lineup. With support for 16 NAND channels and capacities up to 32 TB, this U.2 / E3.S SSD has advertised sequential read and write speeds of 14.8 GBps and 11 GBps respectively. Random reads and writes for 4 KB accesses are listed at 3.4 M and 600 K IOPS.
Samsung claims a 1.7x performance improvement and a 1.7x power efficiency improvement over the previous generation (PM1743), making this TLC SSD suitable for AI servers.
The 9th Gen. V-NAND wafer was also available for viewing, though photography was prohibited. Mass production of this flash memory began in April 2024.
StorageSamsung had quietly launched its BM1743 enterprise QLC SSD last month with a hefty 61.44 TB SKU. At FMS 2024, the company had the even larger 122.88 TB version of that SSD on display, alongside a few recorded benchmarking sessions. Compared to the previous generation, the BM1743 comes with a 4.1x improvement in I/O performance, improvement in data retention, and a 45% improvement in power efficiency for sequential writes.
The 128 TB-class QLC SSD boasts of sequential read speeds of 7.5 GBps and write speeds of 3 GBps. Random reads come in at 1.6 M IOPS, while 16 KB random writes clock in at 45K IOPS. Based on the quoted random write access granularity, it appears that Samsung is using a 16 KB indirection unit (IU) to optimize flash management. This is similar to the strategy adopted by Solidigm with IUs larger than 4K in their high-capacity SSDs.
A recorded benchmark session on the company's PM9D3a 8-channel Gen 5 SSD was also on display.
The SSD family is being promoted as a mainstream option for datacenters, and boasts of sequential reads up to 12 GBps and writes up to 6.8 GBps. Random reads clock in at 2 M IOPS, and random writes at 400 K IOPS.
Available in multiple form-factors up to 32 TB (M.2 tops out at 2 TB), the drive's firmware includes optional support for flexible data placement (FDP) to help address the write amplification aspect.
The PM1753 is the current enterprise SSD flagship in Samsung's lineup. With support for 16 NAND channels and capacities up to 32 TB, this U.2 / E3.S SSD has advertised sequential read and write speeds of 14.8 GBps and 11 GBps respectively. Random reads and writes for 4 KB accesses are listed at 3.4 M and 600 K IOPS.
Samsung claims a 1.7x performance improvement and a 1.7x power efficiency improvement over the previous generation (PM1743), making this TLC SSD suitable for AI servers.
The 9th Gen. V-NAND wafer was also available for viewing, though photography was prohibited. Mass production of this flash memory began in April 2024.
StorageAt FMS 2024, Kioxia had a proof-of-concept demonstration of their proposed a new RAID offload methodology for enterprise SSDs. The impetus for this is quite clear: as SSDs get faster in each generation, RAID arrays have a major problem of maintaining (and scaling up) performance. Even in cases where the RAID operations are handled by a dedicated RAID card, a simple write request in, say, a RAID 5 array would involve two reads and two writes to different drives. In cases where there is no hardware acceleration, the data from the reads needs to travel all the way back to the CPU and main memory for further processing before the writes can be done.
Kioxia has proposed the use of the PCIe direct memory access feature along with the SSD controller's controller memory buffer (CMB) to avoid the movement of data up to the CPU and back. The required parity computation is done by an accelerator block resident within the SSD controller.
In Kioxia's PoC implementation, the DMA engine can access the entire host address space (including the peer SSD's BAR-mapped CMB), allowing it to receive and transfer data as required from neighboring SSDs on the bus. Kioxia noted that their offload PoC saw close to 50% reduction in CPU utilization and upwards of 90% reduction in system DRAM utilization compared to software RAID done on the CPU. The proposed offload scheme can also handle scrubbing operations without taking up the host CPU cycles for the parity computation task.
Kioxia has already taken steps to contribute these features to the NVM Express working group. If accepted, the proposed offload scheme will be part of a standard that could become widely available across multiple SSD vendors.
StorageIntel has divested its entire stake in Arm Holdings during the second quarter, raising approximately $147 million. Alongside this, Intel sold its stake in cybersecurity firm ZeroFox and reduced its holdings in Astera Labs, all as part of a broader effort to manage costs and recover cash amid significant financial challenges.
The sale of Intel's 1.18 million shares in Arm Holdings, as reported in a recent SEC filing, comes at a time when the company is struggling with substantial financial losses. Despite the $147 million generated from the sale, Intel reported a $120 million net loss on its equity investments for the quarter, which is a part of a larger $1.6 billion loss that Intel faced during this period.
In addition to selling its stake in Arm, Intel also exited its investment in ZeroFox and reduced its involvement with Astera Labs, a company known for developing connectivity platforms for enterprise hardware. These moves are in line with Intel's strategy to reduce costs and stabilize its financial position as it faces ongoing market challenges.
Despite the divestment, Intel's past investment in Arm was likely driven by strategic considerations. Arm Holdings is a significant force in the semiconductor industry, with its designs powering most mobile devices, and, for obvious reasons, Intel would like to address these. Intel and Arm are also collaborating on datacenter platforms tailored for Intel's 18A process technology. Additionally, Arm might view Intel as a potential licensee for its technologies and a valuable partner for other companies that license Arm's designs.
Intel's investment in Astera Labs was also a strategic one as the company probably wanted to secure steady supply of smart retimers, smart cable modems, and CXL memory controller, which are used in volumes in datacenters and Intel is certainly interested in selling as many datacenter CPUs as possible.
Intel's financial struggles were highlighted earlier this month when the company released a disappointing earnings report, which led to a 33% drop in its stock value, erasing billions of dollars of capitalization. To counter these difficulties, Intel announced plans to cut 15,000 jobs and implement other expense reductions. The company has also suspended its dividend, signaling the depth of its efforts to conserve cash and focus on recovery. When it comes to divestment of Arm stock, the need for immediate financial stabilization has presumably taken precedence, leading to the decision.
CPUsThe CXL consortium has had a regular presence at FMS (which rechristened itself from 'Flash Memory Summit' to the 'Future of Memory and Storage' this year). Back at FMS 2022, the company had announced v3.0 of the CXL specifications. This was followed by CXL 3.1's introduction at Supercomputing 2023. Having started off as a host to device interconnect standard, it had slowly subsumed other competing standards such as OpenCAPI and Gen-Z. As a result, the specifications started to encompass a wide variety of use-cases by building a protocol on top of the the ubiquitous PCIe expansion bus. The CXL consortium comprises of heavyweights such as AMD and Intel, as well as a large number of startup companies attempting to play in different segments on the device side. At FMS 2024, CXL had a prime position in the booth demos of many vendors.
The migration of server platforms from DDR4 to DDR5, along with the rise of workloads demanding large RAM capacity (but not particularly sensitive to either memory bandwidth or latency), has opened up memory expansion modules as one of the first set of widely available CXL devices. Over the last couple of years, we have had product announcements from Samsung and Micron in this area.
At FMS 2024, SK hynix was showing off their DDR5-based CMM-DDR5 CXL memory module with a 128 GB capacity. The company was also detailing their associated Heterogeneous Memory Software Development Kit (HMSDK) - a set of libraries and tools at both the kernel and user levels aimed at increasing the ease of use of CXL memory. This is achieved in part by considering the memory pyramid / hierarchy and relocating the data between the server's main memory (DRAM) and the CXL device based on usage frequency.
The CMM-DDR5 CXL memory module comes in the SDFF form-factor (E3.S 2T) with a PCIe 3.0 x8 host interface. The internal memory is based on 1α technology DRAM, and the device promises DDR5-class bandwidth and latency within a single NUMA hop. As these memory modules are meant to be used in datacenters and enterprises, the firmware includes features for RAS (reliability, availability, and serviceability) along with secure boot and other management features.
SK hynix was also demonstrating Niagara 2.0 - a hardware solution (currently based on FPGAs) to enable memory pooling and sharing - i.e, connecting multiple CXL memories to allow different hosts (CPUs and GPUs) to optimally share their capacity. The previous version only allowed capacity sharing, but the latest version enables sharing of data also. SK hynix had presented these solutions at the CXL DevCon 2024 earlier this year, but some progress seems to have been made in finalizing the specifications of the CMM-DDR5 at FMS 2024.
Micron had unveiled the CZ120 CXL Memory Expansion Module last year based on the Microchip SMC 2000 series CXL memory controller. At FMS 2024, Micron and Microchip had a demonstration of the module on a Granite Rapids server.
Additional insights into the SMC 2000 controller were also provided.
The CXL memory controller also incorporates DRAM die failure handling, and Microchip also provides diagnostics and debug tools to analyze failed modules. The memory controller also supports ECC, which forms part of the enterprise... Storage
As the deployment of PCIe 5.0 picks up steam in both datacenter and consumer markets, PCI-SIG is not sitting idle, and is already working on getting the ecosystem ready for the updats to the PCIe specifications. At FMS 2024, some vendors were even talking about PCIe 7.0 with its 128 GT/s capabilities despite PCIe 6.0 not even starting to ship yet. We caught up with PCI-SIG to get some updates on its activities and have a discussion on the current state of the PCIe ecosystem.
PCI-SIG has already made the PCIe 7.0 specifications (v 0.5) available to its members, and expects full specifications to be officially released sometime in 2025. The goal is to deliver a 128 GT/s data rate with up to 512 GBps of bidirectional traffic using x16 links. Similar to PCIe 6.0, this specification will also utilize PAM4 signaling and maintain backwards compatibility. Power efficiency as well as silicon die area are also being kept in mind as part of the drafting process.
The move to PAM4 signaling brings higher bit-error rates compared to the previous NRZ scheme. This made it necessary to adopt a different error correction scheme in PCIe 6.0 - instead of operating on variable length packets, PCIe 6.0's Flow Control Unit (FLIT) encoding operates on fixed size packets to aid in forward error correction. PCIe 7.0 retains these aspects.
The integrators list for the PCIe 6.0 compliance program is also expected to come out in 2025, though initial testing is already in progress. This was evident by the FMS 2024 demo involving Cadence's 3nm test chip for its PCIe 6.0 IP offering along with Teledyne Lecroy's PCIe 6.0 analyzer. These timelines track well with the specification completion dates and compliance program availability for previous PCIe generations.
We also received an update on the optical workgroup - while being optical-technology agnostic, the WG also intends to develop technology-specific form-factors including pluggable optical transceivers, on-board optics, co-packaged optics, and optical I/O. The logical and electrical layers of the PCIe 6.0 specifications are being enhanced to accommodate the new optical PCIe standardization and this process will also be done with PCIe 7.0 to coincide with that standard's release next year.
The PCI-SIG also has ongoing cabling initiatives. On the consumer side, we have seen significant traction for Thunderbolt and external GPU enclosures. However, even datacenters and enterprise systems are moving towards cabling solutions as it becomes evident that disaggregation of components such as storage from the CPU and GPU are better for thermal design. Additionally maintaining signal integrity over longer distances becomes difficult for on-board signal traces. Cabling internal to the computing systems can help here.
OCuLink emerged as a good candidate and was adopted fairly widely as an internal link in server systems. It has even made an appearance in mini-PCs from some Chinese manufacturers in its external avatar for the consumer market, albeit with limited traction. As speeds increase, a widely-adopted standard for external PCIe peripherals (or even connecting components within a system) will become imperative.
Storage
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